A detailed examination of pitch discrimination deficits associated with auditory verbal hallucinations in schizophrenia.

Abstract

Individuals with schizophrenia spectrum disorders (SSD) and a history of experiencing auditory verbal hallucinations (AVH) exhibit poor pitch discrimination relative to those with an SSD but no AVH history. The present study extended this research, asking if a lifetime history, and the current presence, of AVH exacerbated the pitch discrimination challenges that are seen in SSD. Participants completed a pitch discrimination task, where the tones presented differed in pitch by either 2%, 5%, 10%, 25% or 50%. Pitch discrimination accuracy, sensitivity, reaction time (RT) and intra-individual RT variability (IIV) were examined in individuals with SSD and AVHs (AVH+; n=46), or without AVHs (AVH-; n=31), and healthy controls (HC; n=131). Secondary analyses split the AVH+ group into state (i.e., actively experiencing AVH; n=32) and trait hallucinators (i.e., a history of, but not actively experiencing, AVH; n=16). Relative to HC, significantly poorer accuracy and sensitivity was detected in individuals with SSD at 2% and 5% pitch deviants, and in hallucinators at 10%; however, no significant differences in accuracy, sensitivity, RT nor IIV were found between AVH+ and AVH- groups. No differences between state and trait hallucinators were observed. A general SSD deficit drove the current findings. The findings may inform future research into the auditory processing capabilities of AVH+ individuals.